1. Field of the Invention.
This invention relates in general to certain new and useful improvements in a lineal measurement circuit and method, and more particularly, to a lineal measurement circuit and method which are capable of measuring the output of a cutting apparatus capable of cutting individual product sections from a larger piece of product stock.
2. Brief Description of the Prior Art.
In the production of wood boards and strips, it is oftentimes desirable to cut several of the boards or other pieces of wood stock to desired lengths and desired widths. For this purpose, there are several types of wood cutting equipment which are capable of ripping wood, that is, cutting along the length of the grain of a piece of wood stock to obtain a desired width of wood product. Moreover, some of this wood cutting equipment is capable of simultaneously cutting a plurality of individual strips or product sections from a piece of wood stock.
One type of production machine which is capable of simultaneously cutting individual sections of wood stock to desired board widths and which board widths may differ from one another, is commercially available and known as a "selective gang rip saw". This type of device uses shadow marks which are projected onto the strip of wood which is being cut or onto a work surface to enable an operator to locate the desired widths. Thereafter, a plurality of individual strips of wood stock are sequentially moved through the saw and individually cut to desired widths and where the widths may differ from one another.
In the operation of these selective gang rip saws, the operator must pre-select the desired individual widths of the strips which are to be ripped from a wood blank or so-called "wood stock". Thus, for example, an operator may have a request for a required quantity of wood strips having a width of 1/2 inch, another desired quantity of wood strips having a width of 11/2 inches, etc. to be cut in the selective gang rip saw. Thus, the operator will establish the spacing between each of a plurality of saw blades so as to rip an individual wood blank or stock into strips having the desired widths.
In many of these selective gang rip saws, five individual saw blades are provided such that the operator may rip a wood stock into as many as six individual strips by properly positioning the saw blades. Moreover, each of these saw blades is simultaneously rotatable and lie in planes generally parallel to one another.
One of the major problems encountered in the cutting, and particularly the ripping, of wood stock is the fact that the wood stock itself is dimensionally rough and uneven. Thus, edges of the wood stock may be non-linear. Moreover, surfaces of this wood stock itself may be marred or the stock may have other imperfections extending through the wood, such as knots or the like.
The operator of the selective gang rip saw will carefully position shadow lines representing the desired widths on the wood stock in order to obtain the optimum cuts from the wood stock. Thus, the operator may intentionally mix the widths of wood stock which are being ripped. As an example, the operator may be cutting one board into individual strips having e.g. 1/2 inch, 1 1/4 inches and 2 inches. However, after cutting of one piece of stock and because of imperfections in the next piece of stock, the operator may immediately switch and cut boards having 1 7/8 inches, which may also be part of an output requirement. Thereafter, the operator would switch back to and continue with the production of the boards having widths of 1/2 inch, 11/4 inches and 2 inches. As a further example, on the successive wood stock, the board itself may not have sufficent wood so that in the next task, only the 1/2 inch and 11/4 inch wood strips may be produced thereby omitting the 2 inch strip from that particular piece of wood stock.
It can be observed that there is no means for effectively measuring the amount of the selected widths of wood strips which have been cut from the wood stock. While it is possible to install a counter on the apparatus in order to determine the lineal footage of wood stock which has passed through the cutting apparatus, it is virtually impossible, with commercially available apparatus, to determine the amounts of the individual strips which have been cut. Thus, in order for the operator to determine the desired quota for each of the individual blanks of wood strip sections has been met, it is necessary for the operator to stop the cutting operation and literally sort the various individual strips into piles of the selected desired widths and thereafter make a rough estimate of the wood section strips which have been cut. This is a particularly pronounced problem when the operator may be cutting several thousand feet of board at one width, several thousand feet of board at another width, etc.
Interference with the cutting operation to enable the operator to measure individual wood strip sections of selected widths is not only time consuming, but clearly impedes other work operations which may require the use of the wood sections cut from the wood stock. In addition, these selective gang wood saws are very expensive pieces of equipment and cost amortization is only effective when they are generally continuously operated. Hence, work stoppage for purposes of measuring is not only unproductive, but is economically undesirable.
In many cases, it is also desirable to determine the efficiency of operation using certain types of wood, as for example, from different wood vendors, or certain grades of wood, or the like. Inasmuch as the selective gang wood saws may be sequentially cutting wood stock from various sources, the output is often times mixed. As an example, an operator of one of these selective gang rip saws may be cutting wood of a first grade and immediately thereafter wood of a second grade or otherwise, cutting wood of a first load and immediately thereafter wood from a second load. Therefore, it is oftentimes difficult to determine the efficiency of operation, that is how much waste resulted from one load or grade of wood compared to another load or grade of wood.